Radiation
Radioactivity can often be found in museum items such as glow in the dark clocks and watches, especially those from the mid-1900s, as well as some ceramics, rocks, and ammunition.
In New Zealand there are naturally occurring radioactive rocks to be found in the Buller Gorge and Hawks Crag. Are some of these in your museum?
Believe it or not, from the 1920s to well into the 1950s, radiation was often touted as being healthy and invigorating. Radioactive minerals were incorporated into ceramics that held water and other liquids so that you could drink liquid that was infused with the invigorating power of radiation! In America, a company called Gilbert produced an “Atomic Energy Lab” kitset for children. It let children learn about radiation by doing experiments. The kit contained uranium!
By what other names are radioactive items known?
Your museum will hopefully not have a Gilbert’s Atomic Energy Lab kit, but you may have minerals such as coffinite, uranite, pyrite, or cinnabar. These may be radioactive. You may also have items from World War ll, such as glow-in-the-dark compasses, watches, or instrumentation from planes. It is the radioactive radium used in the paint that makes these items glow in the dark. Green radioactive glass may also be found in museums.
Why is radiation a hazard we need to think about?
These days, we know there is a link between low levels of exposure to radiation and cancer. The hidden hazard is that we may be putting our staff and visitors at risk of being exposed to small amount of radiation.
Institutions have to ensure that they are not allowing their staff or members of the public to exceed the dose limits laid out by law.
Where might we find radioactive items?
As previously discussed, minerals such as coffinite, uranite, pyrite, or cinnabar may be radioactive, along with any rocks that have come from Hawks Crag in Buller Gorge. This is an area with naturally occurring radioactive rocks.
Coloured glass ornaments, especially yellow glass, may have been coloured with radioactive elements to make it glow in the dark.
Radium was used to paint numbers on glow-in-the-dark clocks, watches, and dials, especially those dials used in WWll bombers and fighter planes.
Some ammunition is made from uranium-depleted metal. This too is radioactive.
Finally, some ceramics, like those pictured above, deliberately incorporated radium and uranium so that the water stored in it would be suffused with healthy radiation. Thousands of these were sold in the USA in the 1930s. The water, and especially fruit juice, stored in these jars, caused lead and arsenic to leach out of the clay into the liquid, thus showing some of our exhibits may contain more than one hidden hazard!
How can we confirm that we have radioactive items?
You can use a Geiger counter to help identify any radioactive items that you may have. If you do not have a Geiger counter and you are based in Otago or Southland, you can contact the friendly Collections teams at Tūhura Otago Museum, who would be happy to loan you one. For those of you located outside Otago and Southland, you can contact Radiation Protection Services.
What does the law say about radioactivity?
Radiation doses and limits are now part of the 2016 Health and Safety (Radiation) at Work Act, and they state that a member of the public (that’s us) is allowed 1 mSv (one thousandth of a Sievert) of exposure per year (not including medical treatment).
To put this in perspective, a CT scan can give you 15.4 mSv and a breast screen x-ray 0.2 mSv, so you can see that the 1 mSv limit sits between an x-ray and a CT scan.
An occupational worker (for example someone who works with x-rays) is allowed 50 mSv in a year but no more than 100 mSv in a 5-year period. This averages out at 20 mSv per year, which is still up to 20 times more than the general public.
According to the Institute of Environmental Science and Research (ESR), the average dose of background radiation that we receive in New Zealand is approximately 1.9 mSv a year.
What do museums, galleries, libraries, and archives have to do if they have radioactive items?
As part of your health and safety plan, you MUST include a radiation safety plan if you have any radioactive items, and the plan would include:
- Identifying and labelling radioactive materials.
- Assessing the risks from your radioactive materials
- Processes for accidents, incidents, emergencies, and disposal of radioactive items
- Documenting staff training
- Reviewing the plan for effectiveness
How can institutions manage radioactive items in their collections?
If you have any concerns regarding radioactive items in your collections, you can contact the radiation hotline on 021 393632. For general information, contact ESR on 03 351 6019 or use this link: https://www.esr.cri.nz/.
If you are based in the Otago or Southland region, you can contact the friendly Conservation staff at Tūhura Otago Museum. They have a Geiger counter and can help if you have concerns and wish to determine if an item is radioactive. A practical step to consider is increasing the distance from the source of the radiation. If an object gives a dose of 40 µSv at 1 m, it will only give a dose of 10 µSv at 2 m distance. If you double the distance you quarter the dose.
If institutions wish to dispose of any radioactive items, how can they do this safely?
Firstly, seek advice from ESR via the link below. Each radioactive item should be assessed on an individual basis as they can emit different types of radiation and need to be treated accordingly.
